How can I export ue4 datasmith object to fbx which have asset user data?

Development Programming & Scripting
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Hi everyone!
I import a Navisworks file into ue4 with datasmith. But it have tens of thousands actors now.So this scene needs optimization a lot！ When I export it to fbx, and open it whith 3ds max.It just lost all of the asset user data which is very importent.
The question is: How can I keep these asset user data in fbx which is export from ue4 datasmith scene?
Thanks!